A microtome is a device used in histological examinations that thinly slices a tissue sample into sections that can be used for microscope examination. To obtain such thinly sliced sections, the microtome usually requires a very sharp knife or blade that moves in a reciprocating motion across the tissue sample, which is often embedded in paraffin or other fixative, or remains fixed and the tissue sample reciprocates across the blade. Typically, the knife or blade may be removed from the microtome because, after repeated use, the blade becomes dull and, therefore, no longer provides cleanly cut, thin sections. As a result, from time to time, a new sharp blade is required to be inserted into the microtome.
The typical microtome blade is optimized for cutting. That is, the common microtome blade is generally an elongate structure that has at least one knife edge that extends the entire length of the blade. In many cases, the common microtome blade has two knife edges on opposite sides of the blade where each knife edge extends the entire length of the blade. In such configurations, the knife edges are exposed to the user of the microtome both during the cutting operation and during the eventual replacement of the blade. For instance, in common microtomes, the user is required to retrieve the cut section from the blade after the reciprocating motion, which exposes the users fingers and hands to the knife edge. Additionally, during blade replacement, the user must handle the blade directly, which also exposes the users fingers and hands to the knife edge. As a result, unintended injuries, such as finger and hand cuts, are possible if the user is not careful, not paying attention, or not experienced with the use of the microtome.
In a laboratory setting, where a microtome is most often used, preventing unintended knife cuts or sharp-object injuries (i.e., sharps' injuries) is of primary importance. However, due to the configuration of typical microtome blades, such as exposed knife edges that extend the length of the blade, unintended cuts during microtome use or blade replacement are frequently encountered in laboratories utilizing microtomes. Attempts to eliminate such unintended cuts generally center around effective training or providing supplemental protective equipment. However, such solutions have shortcomings.
Effective training and safe working procedures are often the first step undertaken by laboratories using microtomes to prevent unintended blade cuts. Such training and procedures often includes education on proper handling of blades, safe procedures for insertion of the blade in the microtome, and safe procedures for operation of the microtome. However, improved training, education, and attention to safe working practices do not eliminate all unintended microtome knife cuts. Often the laboratory worker is rushed, believes that such procedures are unnecessary, or fails to pay attention to a routine procedure that is performed safely many times.
Other attempts at preventing unintended blade cuts involve providing supplemental protective equipment. Such equipment may include special gloves or knife protectors. For example, cut resistant gloves are one type of supplemental protective equipment. However, such gloves may create other unwanted problems. For instance, the user may lose tactile feel with the gloves, which may make it difficult to retrieve the cut sections. Furthermore, the gloves may be bulky, which may complicate the blade replacement procedures. Knife protectors, on the other hand, are another type of supplemental protective equipment. Such protectors typically involve a blade holder or other structure on the microtome itself that includes a safety surface that guards the knife edge. For instance, U.S. Pat. Nos. 1,998,428; 5,092,210; and 5,740,708 are typical microtome blade holders that include examples of protective surfaces. However, such protections also may create other unwanted issues. Such knife protectors are often bulky, require additional assembly steps to install the blade, complicate the operation of the microtome, and involve additional expense to the laboratory.
Consequently, it is desired to obtain a microtome blade having simple safety features to reduce unintended knife cuts that do not hinder the use of the microtome or complicate the blade replacement procedures.